The present invention relates to an emergency communication system terminal apparatus and an emergency communication system which are mounted on a vehicle and serve to transmit data such as positional information of the vehicle to a center in case of emergency. And more particularly, even if the supply of power from a main battery is interrupted due to traffic accidents or failures, the emergency communication system terminal apparatus and an emergency communication system can maintain the operation of the emergency communication system terminal apparatus by the supply of power from an auxiliary battery and can continue the supply of power to a microphone module.
Conventionally, there has been known an emergency communication system terminal apparatus comprising emergency message communicating means which is mounted on a vehicle such as an automobile and serves to carry out a telephone originating process through the base station of a communication service provider to a center for managing an emergency communication system such as a police or an emergency communication center.
The conventional emergency communication system terminal apparatus depends on only the supply of power from a main battery provided in a vehicle. Also in the supply of power to a microphone module, therefore, the supply of power from the main battery is used to generate power.
In the conventional emergency communication system terminal apparatus, however, an auxiliary battery is not mounted. Therefore, there has been a problem in that hands-free voice talking cannot be carried out during an emergency message communicating process because the supply of power to the microphone module is interrupted when the supply of power from the main battery provided in the vehicle is interrupted.
It is supposed that an operator cannot move his (her) body freely and brings a receiver close to ears with difficulty when accidents occur. For this reason, hands-free talking is indispensable.
Therefore, the invention has an object to provide an emergency communication system terminal apparatus and an emergency communication system which can maintain the operation of the emergency communication system terminal apparatus by the supply of power from an auxiliary battery and can continue the supply of power to a microphone module also even if the supply of power from a main battery is interrupted.
In order to solve the problem, the present invention provides an emergency communication system terminal apparatus comprising means for implementing hands-free voice talking when giving an emergency communication by inputting a voice signal from a microphone module, means for generating power to be supplied to the microphone module through power supplied from a main battery provided in a vehicle, and means for switching power supply to the microphone module to generation from power supplied from an auxiliary battery when power supply is interrupted by a failure of the main battery.
With such a structure, in the case that the supply of power is interrupted by the failure of the main battery provided in the vehicle, an operation is maintained by the supply of power from the auxiliary battery and power is generated by the supply of power to the auxiliary battery also in the supply of power to the microphone module. Consequently, it is possible to maintain information transmission through voice talking.
Moreover, each of a source voltage to be supplied to a microphone provided in the microphone module and a reference signal voltage is generated by a separate voltage reducing circuit.
With such a structure, also in the case in which the supply of power from the main battery is interrupted, a voice talking operation can be continued, and tone quality can be prevented from being deteriorated by inhibiting the reference signal voltage from being influenced by a fluctuation in power supply relative to a voice to be input to the microphone in order to separate the power supply to the microphone from a voice reference signal voltage.
Furthermore, conductors dedicated to power supply from the emergency communication system terminal apparatus to the microphone module and a power GND are provided and other conductors are further provided for a microphone voice signal and a microphone voice signal GND.
With such a structure, also in the case in which the supply of power from the main battery is interrupted, the voice talking operation can be continued and the voice signal can be input differentially in the emergency communication system terminal apparatus. Consequently, a noise interference is caused with difficulty and tone quality can be prevented from being deteriorated.
Moreover, a conductor dedicated to power supply from the emergency communication system terminal apparatus to the microphone module is provided, a vehicle housing is used for a power GND, and other conductors are further provided for a microphone voice signal and a microphone voice signal GND.
With such a structure, also in the case in which the supply of power from the main battery is interrupted, the voice talking operation can be continued. In addition, it is possible to reduce the conductors between the microphone nodule and the emergency communication system terminal apparatus by sharing the power GND and the GND of the vehicle.
Furthermore, conductors dedicated to power supply from the emergency communication system terminal apparatus to the microphone module and a microphone voice signal are provided, and a common conductor is provided for a power GND and a microphone voice signal GND.
With such a structure, also in the case in which the supply of power from the main battery is interrupted, the voice talking operation can be continued. In addition, it is possible to reduce the conductors between the microphone module and the emergency communication system terminal apparatus by sharing the power GND and the GND of the microphone module.
Moreover, conductors dedicated to power supply from the emergency communication system terminal apparatus to the microphone module and a power GND are provided, and a voice signal is synthesized and transmitted to the power GND.
With such a structure, also in the case in which the supply of power from the main battery is interrupted, the voice talking operation can be continued and a power supply path and a microphone voice transmitting path can be shared. Therefore, the conductors can further be reduced.